1. Field of the Invention
The present invention relates to improving the ease of determining the selected state of operability of equipment. More specifically, this invention is directed to a visual display and particularly to an illuminated control panel incorporating means for accentuating the selected state of the controlled device or devices. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus of such character.
2. Description of the Prior Art
While not limited thereto in its utility, the present invention has been found to be particularly well suited for use in an environment wherein the background illumination varies from darkness to bright sunlight. The flight deck of an aircraft is an example of such an environment. In an aircraft the state of numerous devices and subsystems are controlled by selector switches which may be located on an instrument console. The instrument console will typically be comprised of a panel of translucent or transparent material on which the selector switches, typically toggle switches of comparatively small size, will be mounted. The panel will usually be back light whereby legends or other indicia associated with each switch actuator or actuator position will be faintly visible during night time operation.
In modern high performance aircarft, and particularly during the execution of a maneuver such as landing approach, the flight crew does not have sufficient time to conduct a visual check to determine the setting of the instrument panel switches. Accordingly, flight crews are taught to "read" an instrument panel through use of their sense of tough; i.e., the instrument panel will be scanned with the fingertips to insure the proper positioning of the switches thereon. Inherent in this common practice is the possibility of incorrect "reading". Even when conditions permit visual checking, the possibility of switch handle position misinterpretation exists because of observer location with respect to the switch.
A means for accentuating the state of the switches on an instrument panel has long been desired. Such a message accentuating means should not interfere with the back illumination of the legends associated with the individual switch actuators nor should the message accentuation means constitute a distraction of the flight crew or interfere with normal operation and "reading" of the instrument panel by touch. Similarly, the message accentuation means should not require additional crew controlled actuators nor should it consume significant space. There has not been available, in the prior art, means for accentuating a message or otherwise providing a readily observable indication of the position of a controller which would meet these general requirements.